#include<bits/stdc++.h>
#define ll long long
#define L x<<1
#define R x<<1|1
#define mid (l+r>>1)
#define lc L,l,mid
#define rc R,mid+1,r
#define OK Ll<=l&&r<=Rr
#define Root 1,1,n
#define rep(x,y,z) for(int x=(y);x<=(z);x++)
#define per(x,y,z) for(int x=(y);x>=(z);x--)
#define repn(x) rep(x,1,n)
#define repm(x) rep(x,1,m)
#define pb push_back
#define e(x) for(int i=h[x],y=to[i];i;i=nxt[i],y=to[i])
#define E(x) for(auto y:p[x])
#define Pi pair<int,int>
#define ui unsigned ll
inline int read(){int s=0,w=1;char c=getchar();while(c<48||c>57) {if(c=='-') w=-1;c=getchar();}while(c>=48&&c<=57)s=(s<<1)+(s<<3)+c-48,c=getchar();return s*w;}
inline void pf(int x){if(x<0) putchar('-'),x=-x;if(x>9)pf(x/10);putchar(x%10+48);}
using namespace std;
const int N=1e6+10,M=1e7+5,inf=(1LL<<31)-1,mod=998244353;
const ll llf=1e18;
inline void add(int &a,int b){((a+=b)>=mod) and (a-=mod);}
inline int Add(int a,int b){return add(a,b),a;}
inline int mul(int a,int b){return 1LL*a*b%mod;}
inline void Mul(int &a,int b){a=mul(a,b);}
inline void red(int &a,int b){add(a,mod-b);}
inline int Red(int a,int b){return red(a,b),a;}
inline int qp(int a,int b){if(!b)return 1;int c=qp(a,b>>1);Mul(c,c);if(b&1)Mul(c,a);return c;}
inline int INV(int x){return qp(x,mod-2);}
int n,a[N],b[N];
inline void Main(){
	n=read();
	repn(i)a[i]=read();
	repn(i)b[i]=read();
	repn(i)if(a[i]==0&&b[i]!=0)return puts("-1"),void();
	bool fl=1;
	repn(i)fl&=b[i]>0;
	if(fl){
		ll ans=0;
		int res=0;
		repn(i){
			if(!res)ans+=abs(a[i]-b[i]),res=b[i]-a[i];
			else if(res>0){
				if(b[i]>a[i]){
					if(res>=b[i]-a[i]){
						res=b[i]-a[i];
						continue;
					}
					ans+=b[i]-a[i]-res,res=b[i]-a[i];
				}else ans+=a[i]-b[i],res=b[i]-a[i];
			}else {
				if(b[i]<a[i]){
					if(res<=b[i]-a[i]){
						res=b[i]-a[i];
						continue;
					}
					ans+=a[i]-b[i]+res,res=b[i]-a[i];
				}else {
					ans+=b[i]-a[i],res=b[i]-a[i];
				}
			}
		}
		cout <<ans<<'\n';
		return;
	}
	fl=1;
	rep(i,2,n)fl&=a[i]>=a[i-1]&&b[i]>=b[i-1];
	if(fl){
		ll ans=0;
		int res=0;
		int l=1;
		repn(i){
			if(b[i]==0){
				res=min(res,-a[i]);
				ans=-res;
				continue;
			}
			if(!res)ans+=abs(a[i]-b[i]),res=b[i]-a[i];
			else if(res>0){
				if(b[i]>a[i]){
					if(res>=b[i]-a[i]){
						res=b[i]-a[i];
						continue;
					}
					ans+=b[i]-a[i]-res,res=b[i]-a[i];
				}else ans+=a[i]-b[i],res=b[i]-a[i];
			}else {
				if(b[i]<a[i]){
					if(res<=b[i]-a[i]){
						res=b[i]-a[i];
						continue;
					}
					ans+=a[i]-b[i]+res,res=b[i]-a[i];
				}else {
					ans+=b[i]-a[i],res=b[i]-a[i];
				}
			}
		}
		cout <<ans<<'\n';
		return;
	}
	ll ans=0;
	int res=0;
	repn(i){
		if(a[i]+b[i]==0)continue;
		if(b[i]==0){
			if(res<0)ans+=max(0,-a[i]+res),res=min(res,-a[i]);
			else ans+=a[i],res=-a[i];
			continue;
		}
		if(!res)ans+=abs(a[i]-b[i]),res=b[i]-a[i];
		else if(res>0){
			if(b[i]>a[i]){
				if(res>=b[i]-a[i]){
					res=b[i]-a[i];
					continue;
				}
				ans+=b[i]-a[i]-res,res=b[i]-a[i];
			}else ans+=a[i]-b[i],res=b[i]-a[i];
		}else {
			if(b[i]<a[i]){
				if(res<=b[i]-a[i]){
					res=b[i]-a[i];
					continue;
				}
				ans+=a[i]-b[i]+res,res=b[i]-a[i];
			}else {
				ans+=b[i]-a[i],res=b[i]-a[i];
			}
		}
	}
	cout <<ans<<'\n';
}
signed main(){
	freopen("game.in","r",stdin);
	freopen("game.out","w",stdout);
	int T=read();
	while(T--)Main();
	return 0;
}